Commercial or public buildings are typically required by law to provide for an emergency exit in case of the occurrence of an adverse event, such as a fire. One common type of emergency exit is a latch-closed double door where both doors are mounted within a single door frame. Another common variety of an emergency exit is a latch-closed single door mounted within a door frame. An exit device at the door may be used by individuals to quickly exit the building via the emergency exit. Different types of exit devices include panic bars, push pads, and pushbars. A pushbar is typically located on a door at a convenient height for an individual to push when exiting through the door. Pushing the pushbar actuates retraction of a latchbolt, thereby allowing the door to be opened.
The legal requirements of emergency exits and exit devices include a requirement for maximum fire containment. As a result, the doors are equipped with fire rated exit devices. In some instances, fire hose streams and other external forces can be exerted on exit device components and may create unintentional mechanical inputs from the egress side of the door, potentially causing the door to open and resulting in fire propagation or spreading.
What is therefore needed is a pushbar having a disabling mechanism to substantially prevent latchbolt retraction which could enable the door to be unintentionally opened, possibly resulting in fire propagation or spreading.